This invention relates generally to calculating apparatus usable in digital signal processing devices such as sonobuoys and particularly to a computer wherein a running average of a sequence of data samples may be calculated by adding each successive sample to the produce of the previous average and the previous number of samples and dividing the new total by the sequence number of the new sample.
In processing data signals of a digital processing system such as found in a sonobuoy, it is desirable to compute an average value of the input signals to the sonobuoy over a given period of time. In this manner short term transients as well as other unwanted sonic perturbations are normalized within the system and thus a more effective indicator of target signatures within an ensonified area over a predetermined period of time is provided. Prior art devices for computing the average of a given predetermined quantity of data samples stored and summed the various data samples which were eventually divided by the number of samples taken. Accordingly, prior art devices required relatively large memories and calculated an average value at the end of a predetermined time period. Sonobuoys, to be most effectively applied for their intended purposes, require light weight, compact assemblies that preferably house simplistic circuits consonant with the degree of effectiveness required.